Method of making spirally-grained seamless tubing



s. c. GAT ES METHOD OF MAKING SPIRALLY GRAINED SEAMLESS TUBING FiledApril 18 1922 samaaz 'aaazes mummy Patented Feb. 10, 1925..

UNITED stares SAMUEL C. GATES, OF SHELBY, OHIO.-

v METHOD or MAKING SPIRALLY-GRAINED SEAMLESS TUBING.

. Application flIed"Apri118,1922. semi No. 554,498.

- To all whom it may concern:

Be it known that I, SAMUEL G. GATES,

' a citizen of the United States, residing at laid- Shelby, in thecounty of Richland and State of Ohio, have invented certain new anduseful Improvements in Methods of Making Spirally-Grained SeamlessTubing, of which the following is a specification.

' The present invention relates to the art of making tubes or pipes, andmore particularly to those of the seamless character.

An object is to provide an improved method of manufacturing a seamlesstube which materially increases the strength of the finished product;which reduces the likelihood of destroying the blanks being worked;which reduces the length of the time period for drawing the tubes; whichprevents the breaking of the tube during drawing; and which disposes thefibers ot' the tubes at an angle to the longitudinal axes thereof forresisting rupture incident to handling in the practice of the method andto internal pressure during subsequent use.

Another object of the invention is to provide a seamless tube which isrelatively strong and which is capable ofsustaining considerablebursting pressure, and which has its fibers disposed to extendsubstantially. lengthwise of the direction of the strain to resistseparation'of the fibers and to directly take up the strain.

A further object of this invention is to provide a spirally grainedseamless steel tube possessing the above and various other advantagesand which may be drawn through the die by revolving jaws caused to turnaxially to a desired degree proportionate tothe length of travel of thejaws.

The above and various other objects and advantages of ,the improvedmethod and roductof this invention will be in part "rought out in, andin part understood from, the following detailed description, taken inconnection with the accompanying drawing, in which- Fig. 1 is a sideelevation of a blank or billet 1 from which the seamless tube is formed;4

Fig. 2 is a similar view of the blank after being punched out;

Fig. 3 is a transverse section taken. on the line 3 3 of Fig. 2, showinguneven thickness of the annular wall of blank such as frequently occursincident to punchs;

Fig. 4 is a side elevation of the blank of Fig. 2 clamped at oppositeends between palrsof relatively movable pliers, the latter being turnedaxially atan angle to each other and the blank being correspondinglytwisted to dispose the lateral enlargement spirally about the tube;

Fig. 5 is atransverse section taken on the line 5-591 Fig. 4;

Fig. 6 is aside elevation, partly in section, of a conventional drawingmachine having the twisted tube mounted therein and ready to be drawn;

Fig. 7 is a side elevation partly in section of a novel form of drawingmachine having the tube blank of Fig. 2 applied thereto, andillustrating a modification in the process wherein the tube vis twistedas it is drawn through the die;

Fig. 8 is a transverse section through the same taken on the line 88 ofFig. 7; and,

Fig. 9 is a side elevation, enlarged, of a portion of a finished-tube,showing diagrammatically the angular disposition of the fibers of thefinished tube.

Referring to the drawing, the blank or billet is shown at 10 in Fig; 1,and this blank is in the form of a solid cylindrical body oiisteelorother suitable material from which the tube may be formed. This billet10 is heated to the required temperature and punched or pressed outaxially in the usual manner and is not only elongated and reduced indiameter as shown at 10 in Fig. 2, but is also formed with an axial bore11- providing the interior chamber or passage of the tube.

This is the usual preliminary step in the process or method ofmanufacturing seamless tubing, and as shown in Fig. 3 at .12, theannularwall is very frequently thicker at one side than at the other sides asit is difiicult to form the blank 10 with a truly consecutive bore oropening 11.

In the manufacturing art it has heretofore been found that when theblank 10' is drawn through the die, such as shown in Fig. 6, the unevenor thickened side 12 otters considerably more resistance to passe ethrough the die than the other sides of the blank. This results in theuneven drawing of the tube and in the piling up an increasing shoulderside The Tilt shoulder so accumulatmg against the die at one side of thetube finally increases the strain on the tube to such'point as to causethe blank 10 to break in or beyond the die and to destroy the partlyformed product, or to weaken the product by the uneven drawing action.

To remedy this defect the blank 10 is tortionally twisted either beforedrawing or during the drawing operation.

In Figs. 4 and 5, the blank, after being again heated, is axiallytwisted as at 10 so as to dispose the thickened side of the blankspirally as shown at 12. This twisting may be accomplished in anysuitable manner as by use of two pairs of pliers 13 and 14 which mayengage the opposite ends of the blank and be relatively and axiallyturned to any desired degree, such as shown in Fig. 4.

After twisting, the tube blank 10 may be placed in a drawing machine, asshown in Fig. 6. The drawing machine, is of conventional form andgenerally comprises a. draw head 15 having a die plate 16 therein, apair of pliers or tongs 17 at the outer side of the draw head, and acore rod 18 supported at one end remotely from the draw head 15 andextending at its other end into the opening of the die plate 16. Theblank 10 is reduced at one end as at 19 and placed on the rod 18 withthe reduced end projecting through the die plate 16 and engaged by thepliers 17. The pliers 17 are now moved away from the head 15 and thetube blank 10 is drawn through the die plate 16 and about the end of therod 18, forming a tube of the desired external and internal diameters.As the enlargement 12' of theblank 10 is formed spirally about the tubeblank, the pressure of the thickened side is distributed about all sidesof the blank and the pressure is uniform and the uccummulating shoulderis eliminated and worked into the intermediate spiral side walls of theblank to produce a uniformly thick annular wall in the finished product.

As a modification of the above described process of method, the blank 10of Fig. 2 may have one end 20 reduced and may be mounted on the core rod21 of Fig. 7 with the reduced end 20 extending through the die plate 22.The die plate 22 is supported in a suitable head 23 shown in the presentinstance as of cylindrical form and in which is mounted a pair of pliers24 for grasping the reduced end 20 of the tube blank 10. The pliers 24;are mounted to turn axially with respect to the blank 10 and may berotated in any suitable manner during the drawing action. Asillustrating one way in which the pliers may be drawn and rotated, inFigs. 7 and 8 is shown a gear wheel 25 fixed to the pliers at its pivot26 and which has annularly curved collars 27 at opposite sides of thegear wheel 25 for fittmg 1n forks 28 which rise from the carriage 29which is connected to the chain 30 or other suitable feeding device.

The chain 30 may be mounted upon a sprocket wheel 31 or the like and isadapted to be moved in such direction as to carry the upper lap of thechain 30 outwardly from the die plate 22 for moving the pliers 24 awayfrom the die plate and thus drawing the tube blank through the die. Thehead or casing 23 is provided with a irally disposed rib 32 on'its innerside :dapted to engage in a transverse curve 'or slot 33 formed acrossthe periphery of the gear 25 for the purpose of advancing the gear 25through the desired number of degrees proportionate to the length of thepath of travel of the pliers. The pipe is thus not only drawn throughthe die but simultaneously twisted through the desired angle toconsecutively change any uneven lateral pressures on the tube blankabout the sides of the tube so that an equally drawn tube is producedwhich is not only of uniform thickness throughout its annular wall butwhich is of uniform strength and which is not liable to crack or breakat any one side during the drawing action.

In Fig. 9 is shown a fragment or portion of a finished tube 34 havingthe axial opening or bore 35 and which has been tortionally twistedaccording to the present invention so as to dispose the normallylongitudinal fibers 36 of the tube spirally or at an angle to thelongitudinal axis of the tube For taking up strains tending to crack orburst the tube longitudinally of the fibers. Such disposition of thefibers materially increases the strength of the tube as well as"Facilitating the carrying out of the various steps of the method orprocess with greater accuracy, the exercise of less skill than isusually required, and with a considerably regluccd percentage ofdistorted blanks and in es.

It is obvious that various changes and n'iodifications may be made inthe details of construction and design of the above specificallydescribed embodiment of this invention without departing from the spiritthereof, such changes and modifications being restricted only by thescope of the following claims:

VVhat is claimed is: I

1. That method of manufacturing seamless tubing, which consists inpunching out a solid blank into tubular blank form, tortionally twistingthe tubular blank to dispose lateral inequalities spirally about thetubular blank, and drawing the twisted blank to the desired internal andexternal diameters.

2. That method of making spirally grained tubing, which consists intwisting a weaves tubular blank to dispose lateral inequalities and thefibers of the blank spirally therein, and drawing the twisted blank tothe desired size of the finished tube.

3. That method of making spirally grained tubing, which consists inaxially twisting a tubular blank to dispose lateral inequalities in.spiral fashien about the blank, and drawing said twisted blank straightthrough a die for equallizing lat- Ml eral pressure on the tube beingdrawn.

In testimony whereof I afix my signature.

SAMUEL O. GATES.

